She said the BJP had raised the issue during the during 2011 assembly polls in Uttar Pradesh and a report in a newspaper Monday had validated the party's charges.

"The BJP submitted reports to the authorities that Anand Kumar had floated over 76 companies and through laundering of slush money, was acquiring wealth disproportionate to his known source of income."

Sitharaman said the BJP allegations had highlighted that these companies had invested in companies incorporated in tax havens and his relationship with the chief minister "was being unfairly and illegally exploited".

"The BJP demands a thorough inquiry into these allegations on companies which are incorporated all over the country. Will the finance ministry issue notices to these companies? Will field based enquiries be conducted on these companies?" she asked.

Sitharaman said there were "several unexplained cash inductions into the companies, huge profits earned from sale of undisclosed and unidentified properties and sale of shares at premium rates of tinsel worth companies".

Maintaining that the BSP chief's brother has lots of answers to give, she said Mayawati was a strong ally of the Congress-led government and allegedly helped it in parliament on the issue of foreign direct investment (FDI) in multi-brand retail.

"During the debate on FDI in multi-brand retail, Mayawati's double speak was watched by the entire country," she said.